Be Informed About Rat Bite Fever

Infected rodents can put people at risk of contracting rat bite fever if precautions are not followed.

An infected rat might spread bacteria on his fur during grooming, which can be transferred to an owner who touches or kisses the rat. Via Amelia White/Flickr

By Leticia Materi, PhD, DVM

Years ago, a friend of mine had a pet rat. The rat, Fast Eddie, was extremely intelligent, trainable and had quite a friendly disposition. It was truly remarkable how quickly he could figure out a maze and seemed very content to sit on his owner’s lap. He was a great pet.

While I now live in a province where rats are not allowed as pets (much like California’s ban on ferrets), I still read about common rat illnesses and the zoonotic diseases they carry just in case one day the law changes. One such zoonotic disease that pet owners should be aware of is rat bite fever.

Rat bite fever is a rare disease due to one of two bacteria: Streptobacillus moniliformis and Spirillum minus. In North America, Streptobacillus moniliformis is more commonly isolated. Both bacteria are considered to be part of the normal flora in rats. These bacteria often reside within the oral cavity and throat of the rats and, in general, do not cause the rats any harm.

In spite of its name, rat bite fever can be spread to humans in ways other than bites. Because rats groom themselves, they spread saliva containing bacteria all over their bodies. Thus, disease can be spread when a human kisses the rat, gets a scratch, handles the rat then touches their mouth or food with contaminated hands, and so on. Humans can also contract this disease if they consume products such as milk or other dairy items, water or food contaminated with the bacteria. This disease can also be transmitted by animals other than rats, including mice and gerbils. It does not appear to be spread from person to person.

In humans, signs of disease can vary from person to person. The list of symptoms includes: rash, muscle pain, joint pain and/or swelling, chills, fever, vomiting, headache and swelling near the bite/scratch. Symptoms can occur within 3 days to 3 weeks of infection.

It is important that a medical doctor be consulted if rat bite fever is suspected so that appropriate tests and treatments can be completed. Without proper treatment, this disease can progress to pneumonia, heart infection, brain infection or death.

Good hygiene and obtaining dairy products, food and water from rodent-free sources are important for preventing the spread of this disease. Pregnant women, young children and immunocompromised individuals should avoid contact with rats. Use gloves when cleaning cages and be sure to always thoroughly wash your hands with soapy water after handling rats or cleaning cages to reduce the chance of infection. Thoroughly clean bites and scratches and consult your doctor immediately.

Because the bacteria that cause rat bite fever are part of the normal bacterial population in rats, it is practically impossible to eliminate them from these rodents. Consult with your veterinarian and doctor to further discuss the risks of this disease.

Note: This article is meant for educational purposes only and in no way represents any particular individual or case. It is not for diagnostic purposes. If your pet is sick, please take him or her to a veterinarian.

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Article Categories:
Critters · Mice and Rats